SAT Solver Truth Table Construction Eliminates CNF Conversion Overhead

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Solution Overview

Problem

Existing SAT solvers face significant computational overhead and inefficiency in solving small-sized Boolean satisfiability problems due to the need for Conjunctive Normal Form (CNF) conversion, which introduces additional variables and clauses, and is not friendly for hardware implementation, leading to performance and capacity issues in hardware-based SAT solvers.

Innovation Solution

The approach involves constructing truth tables using Boolean vector interpretation to directly solve small-sized SAT problems, reducing the overhead of CNF conversion and improving performance by representing Boolean formulas as superpositions of bitwise unary and binary Boolean operators, and using iterative methods to assign values and infer variable values efficiently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional SAT solvers use CNF conversion to solve Boolean satisfiability problems, then they can handle general SAT problems, but they introduce significant computational overhead and additional variables and clauses

Engineering Contradiction:
Improveability to solve general SAT problemsVSAvoidcomputational overhead and number of variables and clauses
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extracts and removes the CNF conversion step from the SAT solving process. By directly working with the original Boolean formula representation instead of converting to CNF, the method eliminates the computational overhead and additional variables/clauses that CNF conversion introduces, while still maintaining the ability to solve general SAT problems through direct interpretation and truth table analysis

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of the conventional approach of converting Boolean formulas to CNF form before solving, the patent inverts the process by directly interpreting and analyzing the original Boolean formula structure. This inversion allows the solver to work with the native representation, avoiding the overhead of conversion while preserving problem-solving capability through alternative methods such as truth table construction and direct satisfiability checking

Inventive Principle:
Principle #13The other way round (Inversion)

2Reliability

If conventional SAT solvers convert Boolean formulas to CNF form, then they can solve SAT problems, but hardware implementation becomes inefficient and capacity is reduced

Engineering Contradiction:
Improvecorrectness of SAT problem solvingVSAvoidperformance and capacity of hardware-based SAT solvers
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent substitutes the mechanical CNF conversion process with a direct interpretation and truth table analysis approach. In hardware implementations, this replacement eliminates the need for complex conversion circuits and enables more efficient direct evaluation of Boolean formulas, thereby improving both performance and capacity while maintaining solving correctness

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental parameter of representation from CNF form to direct Boolean formula interpretation. This parameter change allows hardware solvers to operate more efficiently by working with the original formula structure, reducing the capacity requirements and improving performance while maintaining the reliability of SAT problem solving through alternative evaluation methods

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS11232174B1SAT solver based on interpretation and truth table analysis
Publication Date: 2022.01.25 SYNOPSYS INC
  • US11232174B1 patent drawing
  • US11232174B1 patent drawing
  • US11232174B1 patent drawing

AI summary

Techniques and systems for solving Boolean satisfiability (SAT) problems are described. Some embodiments solve SAT problems using efficient construction of truth tables. Some embodiments can improve performance of SAT solvers by using truth tables instead of incurring the overhead of Conjunctive Normal Form (CNF) conversion.